Two Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658
In this work, we report periodicity search analyses in the gamma-ray light curve of the blazar S4 0954+658 in monitoring undertaken by the Fermi Large Area Telescope. Four analytical methods and a tool are adopted to detect any periodic flux modulation and corresponding significance level, revealing...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acca7b |
| _version_ | 1827829172589821952 |
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| author | Yunlu Gong Shiting Tian Liancheng Zhou Tingfeng Yi Jun Fang |
| author_facet | Yunlu Gong Shiting Tian Liancheng Zhou Tingfeng Yi Jun Fang |
| author_sort | Yunlu Gong |
| collection | DOAJ |
| description | In this work, we report periodicity search analyses in the gamma-ray light curve of the blazar S4 0954+658 in monitoring undertaken by the Fermi Large Area Telescope. Four analytical methods and a tool are adopted to detect any periodic flux modulation and corresponding significance level, revealing: (i) a quasi-periodic oscillation (QPO) of 66 days with a significance level of >5 σ spanning over 600 days from 2015 to 2016 (MJD 57,145–57,745), resulting in continuous observation of nine cycles, which is one of the longest cycles discerned in blazar gamma-ray light curves; (ii) a possible QPO of 210 days at a moderate significance of ∼3.5 σ , which lasted for over 880 days from 2020 to 2022 (MJD 59,035–59,915) and for four cycles. In addition, we discuss several physical models to explain the origin of the two transient QPOs and conclude that a geometrical scenario involving a plasma blob moving helically inside the jet can explain the timescale of the QPO. |
| first_indexed | 2024-03-12T04:00:10Z |
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| id | doaj.art-e8b61222be7c4f398479d7a6d4ed3f72 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:00:10Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj.art-e8b61222be7c4f398479d7a6d4ed3f722023-09-03T11:44:29ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194923910.3847/1538-4357/acca7bTwo Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658Yunlu Gong0https://orcid.org/0000-0003-3326-2173Shiting Tian1Liancheng Zhou2Tingfeng Yi3https://orcid.org/0000-0001-8920-0073Jun Fang4https://orcid.org/0000-0001-8043-0745Department of Astronomy, School of Physics and Astronomy, Key Laboratory of Astroparticle Physics of Yunnan Province, Yunnan University , Kunming 650091, People's Republic of China ; fangjun@ynu.edu.cn, gyunlu2021@163.comDepartment of Astronomy, School of Physics and Astronomy, Key Laboratory of Astroparticle Physics of Yunnan Province, Yunnan University , Kunming 650091, People's Republic of China ; fangjun@ynu.edu.cn, gyunlu2021@163.comDepartment of Astronomy, School of Physics and Astronomy, Key Laboratory of Astroparticle Physics of Yunnan Province, Yunnan University , Kunming 650091, People's Republic of China ; fangjun@ynu.edu.cn, gyunlu2021@163.comPhysics Department, Yunnan Normal University , Kunming 650092, People's Republic of China ; ytf@ynnu.edu.cnDepartment of Astronomy, School of Physics and Astronomy, Key Laboratory of Astroparticle Physics of Yunnan Province, Yunnan University , Kunming 650091, People's Republic of China ; fangjun@ynu.edu.cn, gyunlu2021@163.comIn this work, we report periodicity search analyses in the gamma-ray light curve of the blazar S4 0954+658 in monitoring undertaken by the Fermi Large Area Telescope. Four analytical methods and a tool are adopted to detect any periodic flux modulation and corresponding significance level, revealing: (i) a quasi-periodic oscillation (QPO) of 66 days with a significance level of >5 σ spanning over 600 days from 2015 to 2016 (MJD 57,145–57,745), resulting in continuous observation of nine cycles, which is one of the longest cycles discerned in blazar gamma-ray light curves; (ii) a possible QPO of 210 days at a moderate significance of ∼3.5 σ , which lasted for over 880 days from 2020 to 2022 (MJD 59,035–59,915) and for four cycles. In addition, we discuss several physical models to explain the origin of the two transient QPOs and conclude that a geometrical scenario involving a plasma blob moving helically inside the jet can explain the timescale of the QPO.https://doi.org/10.3847/1538-4357/acca7bActive galactic nucleiBlazarsJetsPeriod search |
| spellingShingle | Yunlu Gong Shiting Tian Liancheng Zhou Tingfeng Yi Jun Fang Two Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658 The Astrophysical Journal Active galactic nuclei Blazars Jets Period search |
| title | Two Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658 |
| title_full | Two Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658 |
| title_fullStr | Two Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658 |
| title_full_unstemmed | Two Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658 |
| title_short | Two Transient Quasi-periodic Oscillations in γ-Ray Emission from the Blazar S4 0954+658 |
| title_sort | two transient quasi periodic oscillations in γ ray emission from the blazar s4 0954 658 |
| topic | Active galactic nuclei Blazars Jets Period search |
| url | https://doi.org/10.3847/1538-4357/acca7b |
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